Lecture 6 2/1/24 Flashcards
What are the general characteristics of Strongylida superfamily Trichostrongyloidea?
-males with caudal copulatory bursa
-buccal cavity with reduced/absent teeth
-thin-shelled, morula stage eggs
-most found in G.I. tract
-direct life cycles
-limited larval migration
-seen in ruminants, swine, horses, cats, birds, camelids
-pathogenic
What size eggs are seen in Trichostrongyloidea?
60-108 um
What are the characteristics of Trichostrongylus axei?
aka stomach worm, bankrupt worm, or black scour worm
-DH is cattle, sheep, goats, horses, swine, rabbits, people
-found in stomach
-females 3-8 mm
-males 2-6 mm
-PPP of 3 weeks
How Trichostrongylus axei be identified?
-tiny worms
-no visible buccal cavity
-pointed head
-cervical indentation
-well developed bursa in male
What are the characteristics of Trichostrongylus spp. except T. axei?
-intestinal worms
-DH is ruminants
What are the characteristics of Ostertagia spp. in cattle and Teladorsagia spp. in sheep/goats?
-aka brown stomach worms
-DH is ruminants
-male 6-8 mm
-female 8-10 mm
-PPP of 3 weeks
How can Ostertagia spp. be identified?
-tiny buccal cavity with no oral hook
-present cervical papillae
-small or no vulvular flap on female
-symmetrical dorsal lobe on male’s bursa
-caudal annulations on female
What are the characteristics of Ostertagia spp. pathogenesis?
-in abomasum of ruminants
-parasitic larvae found in gastric glands
-cause parasitic gastritis and chronic abomasitis
-projectile diarrhea, emaciation, anemia, and edema/bottle jaw are common signs
-L3 overwinter on pastures and infect during grazing season
What is type 1 ostertagiosis?
larvae mature directly to adults in abomasum without experiencing arrested development
What is type 2 ostertagiosis?
larvae in arrested development become metabolically active and molt to the adult stage
What are the characteristics of Haemonchus spp.?
-aka barber-pole worm
-DH is ruminants
-males 10-20 mm
-females 18-30 mm
-PPP is 2-3 weeks
-most important sheep/goat parasite
-can remove 1/5 of a lamb’s circulating erythrocytes in one day
What are the recognition characteristics for Haemonchus spp.?
-found in abomasum
-white oviducts twisted around red gut in female
-large vulvular flap in female
-prominent cervical papillae
-oral hook in tiny buccal cavity
-asymmetrical flap and dorsal ray on male bursa
Why are all life cycles of the Haemonchus spp. detrimental to the host?
all life stages suck blood
What are the clinical signs of Haemonchus infection?
-anemia with PCV of 25% or less
-hypoproteinemia
-typically NO diarrhea
Which three parasites are found in the abomasum of ruminants?
-Trichostrongylus axei
-Haemonchus spp.
-Ostertagia spp.
What are the characteristics of Cooperia spp.?
-aka cattle bankrupt worm
-DH is ruminants
-male and female adults < 10 mm
-PPP of 2 weeks
-most common in cattle
-developing some drug resistance
What are the characteristics of Nematodirus spp.?
-aka thread-necked intestinal worm
-DH is ruminants
-female 15-25 mm
-male 10-19 mm
-PPP of 3 weeks
-large, football shaped eggs, 200 um
-females only produce a few eggs per day
What are the characteristics of Nematodirus infective stages?
-L3 develops in egg shell and hatches based on environmental stimuli
-L3 must undergo freezing before warm weather in order to hatch (N. battus)
What are the goals of gastrointestinal nematode (GIN) control?
-contain GIN population below disease/production loss-causing levels
-reduce transmission
-reduce drug resistance
-support producer profitability
Why is it important to NOT kill all of the adult parasites when controlling GINs?
killing all adults would leave the DH populations very susceptible to future infections
What is resistance, in terms of parasites?
normal therapeutic dose is no longer effective in achieving >95% reduction in fecal egg counts
How does resistance develop in parasites?
-too frequent deworming
-underdosing
-treating all animals instead of need-based treatment
-treating and moving to a clean pasture - only resistant parasites in the new pasture
How can GIN infections be limited?
-avoid overstocking
-separate young animals from adults ASAP
-feed animals in dry lot
-prevent manure contamination of feed and water
-remove manure often
-provide clean, disinfected/non-infected areas for births
-use selective treatment
-feed well balanced rations
What are the characteristics of the FAMACHA system?
-regular color checks of the mucus membranes of sheep/goat eyes (every 2-3 weeks)
-paleness indicates anemia from blood loss
-treatment based on anemia estimate
-only used for assessing Haemonchus infection
